Electrical systems of aircraft and other specialized vehicles typically include line-replaceable units (LRUs). LRUs are modular electronics systems, which perform various vehicle operations. LRUs generally have input and output electrical connections and an internal bus, typically a serial bus.
Aircraft Communications Addressing and Reporting System (ACARS) is a digital datalink technique and set of standards for transmission of messages between aircraft and ground station and between different intra-aircraft LRUs. An example ACARS standard is the ARINC 429 Specification, available from Rockwell Collins. ACARS may be used for one-way communication or, by using multiple unidirectional systems, two-way communication. ACARS messages typically consist of one or more 32-bit “words”, each of which may include one or more predefined fields that each may contain data values.
Blockchain technology is used to form decentralized cryptocurrency computer networks such as that for Bitcoin. In such networks, blockchains are used to prevent double spending of the cryptocurrency. In general, blockchains function as distributed ledgers, which can track cryptocurrency transactions.